Back up battery systems and often used in electronic devices. One such system is used for electronic control modules (ECM) in vehicles. Electronic control modules play an important role in motor vehicle engine management systems, as indicated by its widespread use in the automotive industry. In most automotive applications, the ECMs are powered by the vehicle electrical system consisting of the battery, alternator, and wiring harness. When the engine is not operating, the main power source is a primary battery with a limited power storage capacity. When the vehicle is not in use for an extended period of time, the main battery may become completely discharged. In addition, extreme temperature, age of the battery, and faulty wiring may also aggravate the problem of a discharging battery.
Electronic control modules process data received from various vehicle sensors, maintain the data in memory, or execute commands in response to operating conditions as sensed by the various sensors.
Many modern ECM's require a power backup in case a primary supply of power is disconnected. Ensuring continuous real time clock (RTC) function is one of the examples when uninterrupted power is necessary to operate the electronics device. Other applications that benefit from having a backup supply of power include applications that require time/date stamped diagnostic codes, error messages, and other retrievable information, such as engine control units (ECU), chassis and transmission controllers, and telematics.
Two primary methods are available for providing a back up energy source to the ECM in the event of an interruption of the primary supply of power. The first remedy is placing a small, secondary rechargeable battery or other energy storage method permanently within the ECM housing to provide a backup power supply. Rechargeable batteries, however, have a finite operating life and require periodic replacement. To be serviced, access to the battery is required, in which case the module seal has to be broken to open the housing.
An alternative method is to provide a backup power supply by using an external battery connected to the harness. However, when the controller is disconnected from the harness during storage or for servicing, the backup battery is also disconnected from the module.
The present inventor has recognized the need for a backup battery supply that is easily accessible, yet sill protected from the environment.
The present inventor has recognized the need for a back up battery that does not require connection to the harness, allowing the harness to be disconnected from the ECM without interrupting the backup battery supply to the ECM.
The present inventor has recognized the need for a simple design for a back up battery system that requires minimal modification to a header connector, and does not require the need for an additional compartment to house the battery.